Liquid fuel burning system and regulating apparatus



March 12,-1940. F.' R. WHITCOMB 2,193,659

LIQUID FUEL BURNING SYSTEM AND REGULATING APPARATUS Filed July 25, 1936In 0677 207. R W

Patented Mar. 12, 1940 Zddhtdh PATENT orri cs LIQUID FUEL BURNING SYSTEMAND REGULATING APPARATUS Forrest R Whitcomb, lwi nchendcn, Mass.Application-1 July 25, 1936, Serial No. 92,613

' 7 Claims.

This invention relates to liquid fuel burning systems and apparatus, andto a device responsive to a condition that is apt to be variable as,

for instance, the pressure in a steam boiler, for

controlling the flow of fuel tothe burner in such manner as to maintainthe condition, as the steam pressure, substantially constant. 7

'My invention particularly relates, although it is not necessarilyrestricted, to the so-calledvaporizing type of liquid fuel or. oilburner; and its fuel supply and control system. A vaporizing type of oilburner consists of a burner having small-openings through a wall thereofthrough which a combustible mixture. of oil vapor and air flows andburns outsidethe burner; The liquid oil that is supplied under pressureto the burner is first vaporized by passing it througha vaporizing tubethat, usually, is heated bythe flame of the burner, The oil vapor isdischarged at a substantial velocity through a small orifice into acombining or mixing tube where it entrain's' suf ficient air forcombustion; and the mixtur e is passed into the burner. Here'tofore, theregulation of the flame has been accomplished by controlling the flow ofoil vapor by a needle valve the point of which projects .into the fuelorifice to regulate the eifective cross-sectional area thereof. a v aVaporizing the oil usually results in the formation of solid carbonparticles which flow with the carbon particles are too large topassthrough the orifice and hence collect around andin' it and thus plugit frequently; and oneof the functions of the needle valve is to breakaway'the" carbon deposit so that the fuel can pass therethrough althoughultimately the end of the needle burns of? to such an extent that theneedle valve point cannot keep the passage clear. the fuel regulatingvalve is objectionable since it has to be packed against the rather highpres; sure and high temperature of the oil vapor and in practice cannotbe maintained constantly tight so that oil vaporleaks out and ignitesand backfires the burner and necessitates the restarting of the fire. 4

An object of the present invention is the provision of a vaporizing typeof burner and a fuel supply therefor wherein regulation of the fuelsupply to the burner is obtained by control of 'the liquid fuel so thattroubles from leaking oil vapor.

This location of predetermined condition as, for instance, a con stantsteam pressure in the boiler. It is an object of the present inventiontoprovide a novel oil fiow regulating system automatically responsive tothe-predetermined condition, as the steam pressure, or to apredetermined manual setting at will, to control'the fiow of oil in suchmanner as to maintainthe predetermined condition constant. I

In particular it is an object of the invention to provide an improvedfuel regulating apparatus so arranged as to provide for a high flow ofoil corresponding usually to the maximum capacity of the burner and alowhow of oil corresponding usually to the amount of oil necessary to keepthe burner in reliable operation, with means responsive to thepredetermined condition as the steam pressure or rate of. combustiondesired to effect the flow of oil at either high or low volume or anypoint in between, in accordance with conditions.

In supplyingoil for the low flame operation of the burner the sizeofjthe orifice through which the liquid fuel passes is relativelyminute, espe cially for a low maximum capacityburner. Such a smallorifice ordinarily cannot be maintained clear of obstruction,notwithstanding that the oil maybe filtered as completely as ispracticable prior'to its passage to the orifice. The usual fuel oils, atleast those present in common use, seem to contain solid matter or waxesthat cannotbe where there is a sharpdrop in pressure'and plug theorifice. v

A further object of the present invention is the provision of anoil-regulating apparatus wherein the control valve is so arranged thatit is caused to move frequently enough to dislodge any collection ofsolid matter that may tend to plug the orifice and so keep the orificeclear.

filtered out but which collect at a smallorifice.

. 0 Another object of the invention is an oil sup:'

ply system having an oil-regulating apparatus that operates tornaintaina constant rate of combustion, for any setting thereof, irrespective ofa fluctuating oil supply pressure.

A further object of the invention is the provision of an oil regulatingvalve subject both to the pressure of the oilsupply and also to thepressure of-th'e oil vapor, both of which can vary, and so arranged asto maintain a constant oil vaporpressure notwithstanding variations ofoil supply pressure and varying conditions, such as varying vaporizingtemperatures, that tend toward varying vapor pressures. The valvefurther is so arrangedthat it can be adjusted, either manually orotherwise, for different vapor pressures and to maintain constant thepressure for which it is adjusted.

A further object of the invention is the provision of an oil regulatingapparatus so constructed and arranged that it is particularly sensitiveto small variations of steam pressure in the boiler heated by the burnerand hence is capable of maintaining the steam pressure constant withinclose limits.

A yet further object of the invention is the provision of an oilregulating apparatus having a steam pressure controlled high flame valvethat is so balanced or constructed that it is unaffected by variationsin the pressure of the oil that it controls.

A further object is generally to improve upon oil burning systems andregulating apparatus therefor.

Fig. l is a plan view illustrating an oil burning system embodying thepresent invention associated with a steam boiler.

Fig. 2 is an enlarged sectional detail of the filter in the oil vaporpipe of thesystem.

Fig. 3 is a side elevation of the pressure regulating apparatus forminga part of the present invention.

Fig. 4 is a sectional view taken along line 4-4 of Fig. 3.

Fig. 5 is a section along line 5-5 of Fig. 4.

Fig. 6 is a sectional detail of the supporting plate for the high flamevalve.

The liquid fuel burning system embodying the present invention is herebyshown associated with the steam boiler I!) having the combustion chamberI2 in which the burner I4 is located. The burner is provided withorifices I6 through which a combustible mixture passes and is burnedabove the burner, and a combining or mixing tube l8 through which themixture of oil vapor and air is directed into the burner. Liquid fuel issupplied under regulated pressure through a pipe 20 having a pass 22that extends through the flame zone or combustion space of the boiler ina position to be sufficiently highly heated to convert the oil thereininto a vapor. The vapor passes through the pipe 24 and through a smallorifice in a nozzle 2| and discharges into the tube 18 wherein itentrains sufficient air for good combustion.

The flow of the liquid oil is regulated by a flow regulating device 23,the operation of which is controlled by a steam pressure in the boilerthrough a steam pipe 25. Oil is supplied preferably under pressure tothe regulating device through a pipe 26 from an oil pump 28 which drawsoil from a suitable supply source. The pump 28 may comprise a singleacting pump having a reciprocating piston 30 operated by a solenoid 32the circuit of which is controlled by a switch 34 so arranged that whenthe piston is at the bottom of its working stroke the solenoid isenergized and raises the piston. The solenoid is de-energized at the topof its suction stroke and the piston returns on a delivering stroke byspring means or the equivalent not shown, the springs supplying thepumping pressure.

The flow regulating apparatus 23 comprises a lower cylindrical casing36, see especially Figs. 3 and 4, the open lower end of which is closedremovably by a plug 38 having a screw-threaded connection with the endof the steam pipe 25. The plug contains a cylindrical recess in itsupper face in which the cylindrical lower open end 40 of an expansiblebellows 42 is secured as soldered in a fluid tight manner. The bellows42 is preferably composed of metal having a plurality of annularcorrugations so that it is capable of lengthwise expansion. The upperend of the bellows is closed and a piston 44 bears loosely thereagainst,the piston being cupped at its lower end to receive the upper end of thebellows so that the two are held against relative lateral displacement.

The piston 44 is capable of free axial movement within the circularopening of a transverse wall 46 of the casing 36, which wall holds thepiston against undue axial displacement, although ordinarily the pistonis out of engagement with said wall. The piston is screw-threaded ontothe lower end of a piston rod 48 which extends through the upper end ofthe casing 36. A pressure adjusting plug 59 loosely surrounds the pistonrod and is screw-threaded into the upper end wall 52 of the casing 36and bears against the upper end of a compression spring 54. The lowerend of the spring bears against a washer 56 which loosely surrounds thelower end of the piston rod and is seated normally upon the top of thepiston 44. Said washer, however, is larger in diameter than said pistonand can overlie and bear upon the wall 46 of the casing 36 at times ofinsufficient steam pressure so as to take the load of the spring fromthe bellows at such times and prevent undue collapse of the bellows. Thepressure adjusting plug 50 is provided with opposed spanner openings 58by which the plug can be rotated to adjust the compression pressure ofthe spring on the piston and hence adjust the steam pressure at whichthe regulating device is maintained to operate.

A valve casing 60 is disposed above the top of the casing 36 and issecured in spaced relation therewith by opposed sets of upper and lowerspacing tubes 62 and 64 which are received loosely on upstanding tierods 66 screw-threaded in ears 68 of the casing 36 and passed looselythrough ears 10 of the valve casing 60, the valve casing being clampedagainst the ends of the upper casing tube 60 by nuts 12 screw-threadedon the upper ends of said tie rods. The valve casing 60 is provided witha liquid fuel inlet passage 14 and a liquid fuel outlet passage 15.Communication between said passages is controlled by a high flame valvemember or stem 18 having a cylindrical upper end terminating in aconical valve face 89 and having an enlarged lower end 92. The valvestem 18 is adapted for free vertical reciprocatory movements in avertical cylindrical stem passage 84 that communicates with the inletpassage 14 through a conduit 86 and with the outlet passage 18 through aconduit 88, the conical end of the valve stem controlling the flow offluid through the passage 88. The lower end of the valve stem 18 isfixed to the middle of a circular stem-supporting disc 90 having upperand lower annular shoulders 92 and an intermediate outstanding annularflange 94. An upper flexible corrugated metal bellows 96 has its loweropen end surrounding and secured in an oil tight manner as soldered tothe upper annular shoulder 92 and has its upper open end similarlysecured to a cylindrical boss 98 of the valve casing 60, therebysurrounding the valve stem. A second lower flexible metal bellows I00has its upper cylindrical open end surrounding and seemed in an oiltight manner to the lower annular shoulder 92 of the disc verticallyextended are free to expand along their own axis and of oil in. theinterior of the bellows is plate. are received on the tie rods 86 andare clamped between the lower and upper spacing tubes 62 and 64. Thevalve stem 18 is provided with an axially directed oil channel Hi6 whichpermits free communication "between the high pressure oil inlet M andthe interior. of the upper bellows 96. The valve supporting disc 9i) isprovided with an oil channel H28 which establishes communication betweenthe two bellows. This arrangement provides a packlessvalve, that is, onethat is permanently oil tight without the use or a packing gland and onewherein the pressure of the inlet oil on the 'valvestem is balanced sothat there is no material tendency for the valve stem to move ineitherdirection due to the oil pressure.

The valve stem sponding' movements of the piston rod 48. To this end ayoke H is fixed to the upper end of the piston rod {58 and hasoppositely disposed arms HZ which are located qn'opposi'ter sides of thevalve bellows and terminate in vertically adjustable screws H 4 havingconical upper ends Ht above which extend locating projections H8. Avalve supporting plate i213 has ears 522 which rest on or. fulcrum uponthe conical'ends N6 of said screws and has apertures HM through whichthe locating projections H8 are loosely extended. This arrangement givesthe plate freedom for rocking movement in directions transversely ,ofthe line through the screws. The plate is providedwith a cup-shapedrecess E26, see especially Figs. 4 and 6, in which the valve stemsupporting disc '90 is located. The bottom wall I28 of said plate isprovided with a pair of diametrically opposed projections or fulcrums I30 angularly displaced 90 from the line of the screws H4 and, whichfulcrum supports the outstanding flange $2 of said disc 90. Said tionsand the fulcrum support for the plate W2 is capable of universal pivotalmovement with respect to the operating yoke H0, and hence the valvemember '78 is free for vertical movement about its own vertical axisirrespective of the alignment of the operating yoke Hi). With thisarrangement both theoperating piston M and the valve member it are freefor movement with a minimum of sidewise restriction since the parts aresupported entirely on flexible bellows which to tilt sidewise in anydirection. The valve is thus capable of responding in a very sensitivemanner to a fluctuation of steam pressure.

As has been stated above, the valve member '18 is free from influence bythe high pressure oil since the pressure of oil on the upper and lowerends of the valve member is substantially equal, the bellows Qt andlilil' being filled with oil at the pressure of the inlet oil. Thepressure supported by the plate Hi l so that the bellows remain ofconstant length regardless of fluctuations of oil pressure. Hence themovement of the valve member under control of the steam actuated bellows42 is independent of the oil pressure and is governed solely by thesteam pressure.

The valve as thus described is adapted to open ble' diaphragm. I32sheethaving a down-turned rim or flange I 33 neck and, i8 isreciprocated by corre.

opening in the diaphragm I39 disc by virtue of these projec- 'entresiliency determined minimum amount of the adjusting screw vaporpressure that causes the movements of the valve are p are sufficient inamplitude burner at times when the high flame valve 78 is closed; Thelow flame valve comprises a flexiformed of a thin flat metal whichsurrounds an upstanding annular flange 54 0f the valve casing till andis secured to said flange in an oil tight manner, as by soldering. Theshallow loil chamber I36 located under the diaphragm and within saidflange communi cates with the outlet passage 78 through a smallconnecting passage 438 age "14 through avalve passage ME) and anintermediate chamber MZthat is open to the inlet passage 'i-i. Anexteriorly and interiorly' screwthreaded neck 24 2 is fixed to andupstands above the diaphragm i3?) and a valve carrying and adjustingscrew M is screw-threaded in said neck. A packing cap M8 is screwthreaded upon said with the packing material therein, seals" said screwagainst leakage of oil thereabout. The. screw M6 has a slender valve rodor stem I56 extended axially therethrough and fixed thereto. Said rodextendsthrough the central and through the valve passage Mt andterminates in" a conical valve member 552 disposed in the passage M2 inpositions to control the entrance of fuel through said passage MB. i ySaidvalve member E52 by reason of said passage I3l is responsive topressure conditions in the'outlet passage 16 and hence to the pressureof the oil vapor conditions in. the: vapor generator 22. 'When thepressure in the outlet passage "it is relatively high due to the valveit being open the pressure acts on the under side of the diaphragm M2 toflex it outwardly thereby moving the low flame valve I52 upwardly andsealing the entrance to the pas sage I452." When,xhowever, the steampressure in the boiler reaches a sufiiciently high point to cause the.high flame valve '13 to close, the pressure inthe outlet passage 76drops due to the discharge of vaporized fuel into the burner. When thepressure is sufliciently low thediaphragm I39 flexes downwardly-due. toits inhermember 5Qt0 open thereby to admit the prefuel to pass to theburner. The minimum amount of fuel may be varied within limits bychanging the setting of Mt. The low' 'fla1'ne valve maintains a constantpressure-oi oil vapor at the nozzle 28 for if the pressure tends to risein the outlet passage it the low flame valve closes somewhat; and if thepres sure drops the low flame valve opens somewhat.

The operation" of the low flame valve is such that it is in continualreciprocatorymovement in order to maintain a constant pressure.condition in the outlet passage. When the valve opens to admit oil theoil is vaporized and builds up a partial closing of the valve member.The valve. member stays in this semiclosed position until the oil hasbeen consumed and the pressure drops whereupon the valve again opens.Such movements of the valve serve to maintain a constant oil vaporpressure. The response-of the valve to varying oil. supply pressures issimilar. Such further frequent enough and to dislodge solid particlesfrom around the valve member and hence to keep the and with the inletpasand causes the low flamevalve A filter H4 is located in the oil vaporpipe 24 between the oil vaporizing pipe 22 and the nozzle 26 to preventthe passage of solid matter into the nozzle. The filter, as illustratedin detail in Fig. 2, comprises a gas tight casing I56 having inlet andoutlet passages I58 and IE0, respectively, between which a filterelement I62 is located in such manner that all of the vapor isconstrained to pass through the filter element. The filter elementcomprises a porous disc of ceramic material such as carborundum or thelike, molded into shape and having a plurality of pores or smalltortuous passages therethrough that are sufficiently small to entrapcarbon and other solid particles in the vapor stream and prevent themfrom passing to the orifice. The combined area of the small pores orpassages through the filter element is sufficiently great so that thefilter element does not offer any deleterious resistance to the flow ofheated vapor even after long periods of use. The use of the filterelement not only prevents the orifice in the nozzle 26 from clogging andthereby permits the fuel regulation to be effected from the liquid oilside of the system but also provides a cleaner flame since it entrapsthe small solid particles that would otherwise pass through the orificeand into the flame to form soot. The filter preferably is located abovethe burner or where it receives sufiicient heat from the flame thereofto prevent it from condensing the oil vapor.

I claim:

1. An oil burning system including an oil burner, oil flow regulatingapparatus for said burner comprising high and low flame valves havingmovable valve members and a common outlet passage connected with saidburner, means [or operating said high flame valve member to change theoil pressure in said outlet passage, and operating means for said lowflame valve member responsive to a predetermined low oil pressure insaid outlet passage to maintain said pressure substantially constant andresponsive to an elevated pressure to move said low flame valve memberinto closed position.

2. An oil burning system including an oil burner, oil flow regulatingapparatus for said burner comprising high flame and low flame valveshaving valve members and a common inlet passage and a common outletconnected with said burner, operating means for said low flame valvemember responsive to a predetermined low oil pressure in said outletpassage for maintaining said pressure substantially constant, andoperating means for said high flame valve member to open. and close itto change the pressure of oil in said outlet passage between wide limitsand to control the operation of said low flame valve member.

3. An oil burning system including an oil burner, oil flow regulatingapparatus for said burner comprising a low flame valve having inlet andoutlet passages, said outlet passage being connected to said burner,means responsive to a low oil pressure in said outlet passage forcontrolling the opening of said valve, and a high flame valve havingmeans for admitting high pressure oil into said outlet passage to effectthe closing of said low flame valve.

4. An oil burning system including an oil burner, oil flow regulatingapparatus for said burner comprising a valve casing having inlet andoutlet passages, said outlet passage being connected with said burner, amovable valve member controlling the flow of oil between said inlet andoutlet passages, a flexible diaphragm at all times responsive to oilpressure in said outlet passage and at the burner, and an adjustingscrew carried by said diaphragm and carrying said valve member, saidscrew being adjustable in the line of operation of said valve memberwhereby to determine the flow of oil through said valve at predeterminedsettings of said valve member, a second passage connecting said inletand outlet passages, and a second valve member in said second passageoperative to admit oil into said outlet passage independently of saidfirst valve member and in amount sufiicient to act on said diaphragm andclose said first valve member and increase the supply of oil to theburner.

5. An oil burning system including a burner, oil flow regulatingapparatus for said burner comprising a valve casing having inlet andoutlet passages, said outlet passage being connected with said burner, amovable valve member controlling the flow of oil between said passages,a flexible diaphragm at all times responsive to oil vapor pressure atthe burner operatively connected with said valve member for varying itsposition in response to different oil pressures on said diaphragm, andmeans for adjusting the relative position of said valve memberindependently of the action of said diaphragm, a second passageconnecting said inlet and outlet passages, and a second valve member insaid second passage operative to admit oil into said outlet passageindependently of said first valve member and in amount sufficient to acton said diaphragm and close said first valve member and increase thesupply of oil to the burner.

6. An oil burning system including a burner, oil flow regulatingapparatus for said burner including a valve casing having inlet andoutlet passages and an annular flange, said outlet passage beingconnected with said burner, a flexible diaphragm secured to said flange,said casing having a valve passage leading from said inlet passage andopening into the space under said diaphragm and a second passageestablishing communication between said space and said outlet passage,said diaphragm being at all times responsive to burner vapor pressure, avalve member in said first passage, and a valve adjusting screw having ascrew-threaded connection with said diaphragm and carrying said valvemember for adjusting the setting of said valve member to regulate therate of operation of said burner, a second passage connecting said inletand outlet passages, and a second valve member in said second passageoperative to admit oil into said outlet passage independently of saidfirst valve member and in amount sufiicient to act on said diaphragm andclose said first valve member and increase the supply of oil to theburner.

'1. In an oil burner system having a burner, means providing an orificefor discharging oil vapor into the burner, means for supplying oil underpressure, the combination therewith of valve means for controlling theflow of oil from said supply to said vaporizing means, said valve meanshaving means responsive to pressure of the oil vapor and operativeautomatically to maintain a constant pressure of oil vapor irrespectiveof variations of pressure of the oil supply, and means for admitting oilto said vaporizing means independently of said valve means in a quantitysufficient to increase the vapor pressure and effect the closing of saidvalve means.

FORREST R.WH1TCOMB.;

